Ground engaging tools with replaceable tips, which are attached to adapters, are commonly used to loosen or break earth, rock, or other materials to aid in its removal. There are various pin fastening means available to attach the replaceable tip to the adapter. During light earth working activities these fastening means are acceptable. When a replaceable tip is subjected to very severe forces, such as found in rock quarry applications, the fastening pin(s) many times become dislocated from the adapter and tip or may be broken. In either case, the tip is released from the adapter and/or the adapter is damaged, costing the equipment owner valuable time and money.
One of the known fastening assemblies is shown in U.S. Pat. No. 601,911 to Donald L. Wood issued on Aug. 31, 1971. In this device, two pins are placed in the tip adapter bore. The pins are retained using a split lock ring disposed in a groove on the outer end of each pin. During operation in harsh environments, the severe forces imparted to the tip and adapter will generally break the pin in the groove area. The pins are also susceptible to pin loss when one or both of the pins are forced inwardly against the spring bias of the split lock ring thus allowing the pin to be dislodged from the bore. In either case, the tip is separated from the adapter and damage occurs.
Another known fastening assembly is provided in U.S. Pat. No. 3,959,901 to Gene Ralph Klett issued on June 1, 1976. arrangement consists of a single pin and a split lock ring, used to attach an earth working tip to an adapter. The pin extends through a bore in the adapter and tip. The pin is held in place by the frictional forces developed between the pin and the biasing force of the split lock ring which is located in a recess in the adapter. Although this assembly is functional in light to moderate applications, it is not totally adequate in demanding work environments. This combination is not as susceptible to pin breakage as reduced area pins. The assembly may be subject to pin loss due to the forces applied by the tip to the pin during certain extreme operations. As the working medium acts on the tip, the tip in turn exerts a force on the pin greater than the frictional force between the split lock ring and the pin. Consequently, the pin moves with respect to the split lock ring and after a period of operation the pin is no longer held in the adapter bore. The pin may also be driven out by the forces applied by the material being handled. With the pin removed, the tip is separated from the adapter and the adapter is damaged if operation
U.S. Pat. No. 3,733,722 to Richard L. Launder issued May 22, 1973 a fastening assembly in which pins used. Each pin assembly is composed of a pair of bars joined by a rubber body and disposed in a bore in the adapter and tip. The pins are subjected to a pinching force on their outer ends which expands the inner ends to retain the pins in the bores. As the earth working device is used, the tip will cause the rubber body to flex. The body will either separate from the bars or fail internally from the flexing. This failure may be aided by the cutting, puncturing, or ripping of the rubber body by the material being handled. The failure could propagate throughout the body and cause it to fail. When the bars and body are no longer one unit, the pieces will fall out of the bore and the tip will no longer be attached to the adapter.
Fastening pin assemblies are used to provide a means to mount replaceable tips to adapters for material handling purposes. When the fastening assembly is not able to retain the tip to the adapter in even the most severe applications, due to its breakage or loss, it is no longer advantageous. The cost of replacing a tip or even a damaged adapter is far greater than the cost of the pin assembly. The fastening pin assembly must remain functional in all work environments.
The present invention is directed to overcoming one or more of the problems set forth above.